The Lamont-Doherty Geological Observatory Isolab 54 isotope ratio mass spectrometer

J. G. England*, A. Zindler, L. C. Reisberg, J. L. Rubenstone, V. Salters, F. Marcantonio, B. Bourdon, H. Brueckner, P. J. Turner, S. Weaver, P. Read

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


The Lamont-Doherty Geological Observatory (LDGO) Isolab 54 is a double focussing isotope ratio mass spectrometer that allows the measurement of thermal ions produced on a hot filament, (thermal-ionization mass spectrometry (TIMS)), secondary ions produced by sputtering a sample using a primary ion beam, (secondary ion mass spectrometry (SIMS)), and sputtered neutrals resonantly ionized using laser radiation, (sputter-induced resonance ionization mass spectrometry (SIRIMS)). Sputtering is carried out using an Ar primary beam generated in a duoplasmatron and focussed onto the sample using a two-lens column. Resonance ionization is accomplished using a frequency-doubled dye laser pumped by an excimer laser. The Isolab's forward geometry analyzer, consisting of an electrostatic followed by a magnetic sector, allows the simultaneous collection of different isotopes of the same element. This instrument is the first to have a multicollector that contains an ion-counting system based on a microchannel plate as well as traditional Faraday cups. A second electrostatic sector after the multicollector is equipped with an ion-counting Daly detector to allow high abundance sensitivity for measurements of large dynamics range. Selectable source, collector, α and energy slits on the instrument allow analyses to be made over a range of mass resolving powers and analyzer acceptances. Recent applications of the instrument have included the analyses of U by TIMS, Hf, Th and Re by SIMS and Re and Os by SIRIMS.

Original languageEnglish
Pages (from-to)201-240
Number of pages40
JournalInternational Journal of Mass Spectrometry and Ion Processes
Issue number3
Publication statusPublished - 1 Dec 1992
Externally publishedYes


  • negative thermal ion mass spectrometry
  • secondary ion mass spectrometry
  • sputter-induced resonance ionization mass spectrometry.
  • thermal ion mass spectrometry


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